The Management of Lake Como

This paper presents a new and heuristic approach for improving the performance of multipurpose reservoirs already in operation. The main characteristic of the method is that the analyst must first learn from the past experience of the manager and synthesize it into a very simple operating rule. Then, the analyst must point out with the help of the manager what the acceptable modifications of such a rule are. Only after these phases have been carried out can possible improvements in the management be obtained by using standard optimization techniques. The method has been applied to the case of Lake Como, (Northern Italy), and the results are quite satisfactory since the major objectives of the management can be substantially improved. The average duration of the floods on the lake shores and the mean volume of the water deficits in the downstream agricultural areas are about halved, without lowering the mean yearly electricity production of the downstream run-of-river plants. Moreover, the advantages of a revision of the active storage and of a possible protection of the shores of the town of Como are also investigated. All the results of this study had a direct impact on the management of the lake. In fact, the proposed operating rule has been programmed on a microcomputer, which is now used every day by the manager as an essential support for his final decision; the active storage was lowered in June 1982 by the Ministry of Public Works, and the sunken part of Como town will be soon repaved and elevated by the Municipality.